Expression and role of miR-34a in bladder cancer.

To investigate the biological function of microRNA-34a (miR-34a) in bladder cancer, the expression of miR-34a was determined using quantitative real-time polymerase chain (qRT-PCR) reaction in 42 cases of bladder cancer. The relationship between the expression of miR-34a and development of bladder cancer was also studied. The mature mimics of miR-34a were chemically synthesized and transiently transfected into human bladder cancer T24 cells. The effects of miR-34a on apoptosis, cell cycle and proliferation in T24 cells were evaluated by flow cytometry and MTT, respectively. The results showed that the low expression rate of miR-34a was correlated with the malignancy and tumor size of bladder cancer. The up-regulation of miR-34a in T24 cells contributed to cell growth and cell cycle arrest, but not caspase-3 pathway. These findings suggest that the relative low expression of miRNA-34a might be involved in the tumorigenesis of bladder cancer.